App note from MAXIM Integrated on LED lighting utilizing power from PoE. Link here
This application note explains that Power-over-Ethernet (PoE) is a technology used in wired local area networks (LANs). PoE delivers power over the same cable that delivers the Ethernet data. Using LED lighting on a PoE network delivers excellent energy efficiency because it minimizes inefficient power-conversion stages for LED lights used in a retrofitted, legacy, AC-powered socket. The application note also explains how powering and controlling LED lights over a PoE network creates the opportunity to use the LED lights in new and novel ways. Examples are given.